DESCRIPTION: The stated goal is to: (1) further develop the formal analogy between occurrence of a biological effect, and measurement of an EMF by the biological system; and (2) to then investigate several classes of biophysical mechanisms. There will be a focus on the change in the number of molecules in a biochemical pathway that arises because of EMF exposure. Another aim is to estimate threshold EMF exposure conditions based on field strength, exposure time and properties of the biological system. Specifically, a one variable and a two variable model for non-linear biochemical reactions will be investigated. To treat stochastic effects, both models will be analyzed by numerical solution of a so-called "master equation".